Disposable rubber products



Aug. l1, 1959 P. G. CARPENTER DISPOSABLE RUBBER PRODUCTS Filed Deo INVEN TOR. P G. :ARPENTER #miam M4 LA T TOR/v5 V5 United States PatentmsPosABLE RUBBER PRODUCTS Paul G. Carpenter, Bartlesville, Okla.,assignor to Phillips Petroleum Company, a corporation of DelawareApplication December 1, 1955, Serial No. 550,247 8 Claims. (Cl. `166-46)This invention relates to disposable rubbery products of manufacture. Inone aspect, the invention relates -to the method of disposing of, insitu, disposable rubbery products.

In various instances it is necessary to use a temporary member in theset-up of a system or machine, and thereafter, to remove the temporarymember when its usefulness or function has been served. For example, itis sometimes desired to utilize a temporary rubber spacer to hold thevalve stem of a remote valve in the open or closed position, andsubsequently, to remove the spacer when the position of the valve is tobe altered, i. e., closed from an open position or vice versa. Anotherexample is when 'the corners of heavy machinery are mounted on temporaryrubber spacers, and the removal of the spacers is deemed necessary toset the machinery in its proper foundation. The foregoing examplesillustrate situations wherein the temporary rubbery spacer undergoescompressive stress inasmuch as a weight or force is continuallymaintained on the spacer. A further example is the use of rubber packersin oil wells. The packer is positioned in the lower portion .of the wellin the annular space between the casing and the tubing thus sealing theannulus. However, when pressures in the oil reservoir have fallen to thepoint where a well will not produce by natural energy, some method ofartificial lift must be used. For this purpose an oil-well pump, such asa reciprocating pump, is lowered through the tubing to the desireddepth; the oil-Well pump being connected to a pumping unit at thesurface by means of sucker rods. In actual operation, the oil-well pumpliterally lifts the uid from the oil formation up the tubing to thesurface for storage in tanks. To secure eicient pump operation it isimportant to maintain gas control in the vicinityl of the pump at theproducing formation. Gas entering the pump with the oil can causeserious loss of etliciency and, at times, may even prevent operation ofthe valves within the pump. This diculty, due to the presence of freegas between the valves of the pump, may be prevented or alleviated byremoving lthe rubber packer in the annulus to permit an escape passagefor the troublesome gas. The gas is then tapped Vfrom the annulus at thesurface to be disposed of as desired. Thus, the oil well illustrationrepresents a situation wherein the temporary rubber spacer functions asa service barrier or seal. A still further example is where a mass, suchas machinery, is to be lowered or raised to dicultly accessible placesby means of a hoist, crane and the like. A temporary rubbery spacer,molded to the desired shape such as dove-tail, barbell, etc., is theconnecting link between the mass to be transported and the hoistingmeans. In this particular situation, the temporary rubber spacerundergoes extensive stress as there is a force continually tending torupture the spacer. =In the preceding illustrations it is readilyapparent that the manual or physical removal of the rubber spacer maybecome a tedious and time-consuming and expensive manipulation.l 'Thenovel rubber spacer of my invention overcomes, in the main, thesediiculties.

Patented Aug. 11, 1959 ICC The following therefore, are objects of theinvention:

An object of this invention is to provide an improved rubbery spacer.

Another object is to provide an improved rubbery spacer which may bechemically disposed of in situ.

Another object is to provide a novel rubbery spacer which serves as aseal in oil wells.

A still further object is the manufacture of a novel rubbery spacer toserve as a temporary member in a system or machine wherein its removalwhen the situa` tion arises may be effected by ignition or burning ofthe' spacer in situ.

A further object is to provide a disposable article of manufactureundergoing continual compressive stress or extensive stress during itsuse as a temporary member in a system.

A yet further object is to provide a disposable rubber spacer whichfunctions as a temporary service barrier in a system.

Other and further objects of this invention will be apparent to thoseskilled in the art upon study of the accompanying disclosure.

The novel rubbery spacer of this invention is composited with componentshereinafter described so that the removal or disposal of the spacer isaccomplished merely by raising its temperature to the combustiontemperature,'such as ignition by an electrical squib, a torch, a fuse,or the' like, and thus, burning the spacer in situ.

The term spacer in this invention designates a seal, packer, support,washer, ball'valve, connecting link, and the like. Artisans skilled inthe art are familiar with such terminology and with their applicationand use in the various fields. i

The spacer of my invention comprises predominantly a mixture of rubberand an voxidant wherein the rubber is in the continuous phase. Therubber component may be natural or synthetic together with itsappropriate compounding ingredients. It is only necessary that therubber have such a Mooney value that it can be worked so that an oxidantcan be blended therewith. Rubbers with Mooney (ML-4) values upto '100are applicable although it is preferable to have a Mooney value in therange of from about l0 to about 40.

The synthetic rubbers can be prepared in any suitable polymerizationsystem, such as emulsion, bulk, or suspension systems. To illustrate, anemulsion polymerization .system aan. be used te prepare homopolymers orcopolymersgf .conjugated f olsns or copolymers of coniugated ,diQlenSwith other monomeric Compounds. The conjugated d iolens which areapplicable include 1,3- butadiene, isoprene, Vchlortylgnrene,2,3-dimethyl-l,3buta diene, methylpentadiene, piperylene, and others.The conjugated vdienes of 4 to 6 carbon atoms are preferred,althoughdienes -o f more than 6 carbon atoms can be used as well as thevarious alkoxy, such as methoxy and ethoxy, and cyano derivatives.Monomeric substances capable of copolymeriyzng with the conjugateddienes are styrene, a-methylstyrene, acrylonitri1e,vand thevinylpyridines, i.e., v`2-vinylpyridine, 2,5-divinylpyridine, 2-methyl-S-Vinylpyridine, B-ethyl-S-vinylpyridine, and others. Anyinitiatorl system can be used, such as the ironpyrophosphate-hydroperoxide, either sugar-free or containing sugar; thesulfoxylate recipe; the persulfate recipe,l and the like. Any suitableemulsifier such as fatty orV iosin acid-soaps can be used. Conventionalshort stops, i.e., t-butylhydroquinone, 2,4-dinitrochlorobenzene,water-"solubledithiocarbarriates, may be employed as well asotheringrefdients ,such as antioxidants. The emulsion polymerizationtemperature is generally in the range of -40 lto 140 F. The treatment ofcrude natural rubber is too well-known to the art to warrant furtherdiscussion thereof.

Regardless of the source of the rubber, as stated previously, it is onlynecessary that the rubber have such a Mooney value that it can be workedso that the oxidant can be blanded therewith. Any suitable oxidant, suchas ammonium nitrate, ammonium perchlorate, Ypotassium perchlorate,potassium nitrate, or mixtures thereof, and the like may be employed.The oxidant and rubber can be mixed in any manner known in the art, suchas by a dispersion blade mixer.

The composition of the rubber spacer of my invention consistsessentially of 50-85 or more parts of oxidant per 100 parts by weight ofrubber binder-oxidant blend. The rubber binder comprises raw rubber,carbon black, plasticizer, antioxidant, vulcanizing agent and othercompounding ingredients as desired, The rubber binder is subsequentlymixed or blended with the oxidant; the blend possessing a. consistencywhich can be molded to the desired shape by injection molding, extrusionmolding, or other molding processes known to the art. Heat treating themolded article, i.e., spacer, at a temperature in the range from about70 to aboutf250 F., preferably from about 140 to about .180? F., and fora period of time between about 3 hours to about 7 days follows, thuspermanently setting or freezing the shape of the spacer.

An oil resistant rubber can be made from Ythe following emulsionpolymerization recipe. i

The emulsion polymerization is carried at a temperature of approximately25 C. for a period of about 15 hours. After shortstopping and removal ofunreacted monomers the polymer is recovered from the latex in aconventional manner.

To 100 parts by weight of the synthetic rubber produced above are addedthe following materials to produce the rubber binder.

Ingredient: Parts by weight Synthetic rubber 100 Carbon black 65 Zincoxide 5 Dibutyl phthalate 10 Philcure-l13 1 1.5 Sulfur 2 Stearic acid lPhenyl--naphthylamine 3 1 N,N-dimethyl-S-tert-butylsulfenyldithocarbamate.

The synthetic rubberv and carbon black are masterbatched andsubsequently there is added to the masterbatch the remaining ingredientslisted above. To this mixture (the components of which now form therubber binder) is added 75 parts of ammonium nitrate per 25 parts byweight of the rubber binder. Substantial uniform distribution of theentire mix can be obtained in a Baker- Perkins dispersion mixer. Therubber binder-oxidant blend is molded to the desired shape and cured 48hours at 170 F.

A molded and cured rubber binder-ammonium nitrate blend consisting vof50 parts by weight of binder per 50 parts by weight-of ammonium nitratewill vignite when it oxidant incorporated into the blend. The ultimateuse of the shaped and cured rubber binder-oxidant blend will, in anumber of instances, govern the choice of the synthetic rubber componentin the blend. For example, in a situation where my novel packer isexposed to hydrocarbons, the synthetic rubber component must be oilresistant, and thus, the use of, for example, the acryloniytrilecopolymers is desired.

The specification is accompanied by a drawing disclosing a specificembodiment of the application of my novel rubbery spacer. The drawing ismerely illustrative and is not to be construed as limiting the scope ofthe invention.

The drawing is a schematic View of a typical oil-well.

In the drawing, the numeral 1 indicates the surface casing set andcemented. This casing is to protect fresh water supplies near thesurface, prevent vthe unconsolidated formations from caving and providea means of controlling the flow of drilling Huid. Within the surfacecasing is oil-string casing 2 also set and cemented. The oil-stringcasing is not ordinarily set in a well until it has demonstrated that itis likely to be a producer. There are generally other casings, such asthe intermediate casing, which are not shown in the simplified drawing.The nal step in preparing the piping for a producing well is running inthe tubing 3 to the bottom of the well or pay zone 4 so that an annularchamber is formed between the tubing 3 and the oil-string casing 2.Packer 5 comprising 75 parts by weight of ammonium nitrate and 25 partsby weight of acrylonitrile-butadiene blend prepared in the mannerexplained above, is fitted in the annulus at the desired depth, and isconnected to electric source 6. An electric squib may either beincorporated into the packer or be adjacent thereto. Within the tubingis reciprocating pump 7, connected by means of sucker rods 8 Ito thepump unit 9 on the surface. The pump technique is ernployed when the oilformation lacks the necessary pressure to ow naturally. As the pistonwithin reciprocating pump 7 is moved upward, ball valve 11 is opened andfluid from pay zone 4 is admitted while ball valve 12 remains in aclosed position. The downward stroke of the piston, closes ball valve 11and opens ball valve 12 wherein the fluid enters the cavityv above thereciprocating pump. In this continuous fashion, the fluid is lifted tothe surface. However, gas entering the reciprocating pump along with thefluid may lodge between the ball valves, thus decreasing the efficiencyof the pump. The gas within the pump is merely compressed and expandedby the action of the pump, and little fluid is thereby lifted throughthe tubing to the surface. When such a situation arises it may benecessary to remove the packer to permit the gaseous buildup at the wellbottom to escape through the annular chamber. The pulling of the packeris a tedious, expensive, time-consuming procedure. With the novel packerof my invention, the packer is merely burned or ignited 'm situ bysetting off the electrical squib by turning on electric source 6. Thepacker can be also ignited by other means, such as lowering a torchthrough the tubing to a point adjacent to the packer. The metal tubingis heated at that point whereby the packer will ignite and burn when theignition temperature is reached. Thus, the gas can escape upward throughthe unimpeded annulus to the surface to be utilized or discarded, asdesired. By the above expedient'the gas can eventually be worked out ofthe reciprocating pump.

The preparation of a typical synthetic rubber, the cornpounding thereof,followed by blending with an oxidant,

is heated to a temperature of approximately '450 F.

prior to molding and curing the blend, has been set out in particulardetail. The application of the molded and cured blend as a packer in anoil well operation has also been set forth. It is not my intent to belimited to this speciiic embodiment. It is desirable that the inventionbe practiced with a natural or synthetic rubber which has 'such a Mooneyvalue, i.e., up to 100, that it can be'worked so that an oxidant can beblended therewith. It will be apparent to those skilled in the art thatvarious modifications and applications of this invention can be madeupon study of the accompanying disclosure without departing from thespirit and scope of the said disclosure.

I claim:

1. As an article of manufacture an oil well packer having an annularresilient seal member consisting essentially of a composition comprisinga rubbery binder selected from the group consisting of natural rubberand synthetic, conjugated diene polymer :and sufficient oxidant inadmixture therewith to supply the oxygen necessary for combustion withsubstantial decomposition of said packer, thereby rendering said packerboth ignitible and self-sustaining in combustion even in the absence ofany external source of oxygen.

2. As an article of manufacture an oil well packer having an annularresilient seal member consisting essentially of a composition comprisinga mixture of rubbery binder selected from the group consisting ofnatural rubber and synthetic, conjugated diene polymer and from 50 to 85parts by weight per 100 parts olf mixture of oxidant selected from thegroup consisting of ammonium nitrate, ammonium perchlorate, potassiumnitrate, potassium perchlorate, and mixtures thereof, thereby renderingsaid packer both ignitible and self-sustaining in combustion tosubstantial decomposition thereof even in the absence of any externalsource of oxygen.

3. An article of manufacture according to claim 2 wherein said rubberybinder is a copolymer of butadiene and acrylonitrile.

4. In an operation wherein the application of a force is adapted to betemporarily restrained and subsequently released, the improved methodwhich comprises positioning in the path of said force a body consistingessentially of a composition comprising a rubbery binder selected fromthe group consisting of natural rubber and synthetic, conjugated dienepolymer and sufiicient oxidant in admixture therewith to supply theoxygen necessary for combustion with substantial decomposition of saidbody, thereby rendering said composition both ignitible andself-sustaining in combustion even in the absence of any external sourceof oxygen, and igniting said body in situ so that said bodysubstantially decomposes.

5. A method of packing oit and subsequently removing the packingmaterial from an oil well which comprises positioning in said Wellpacking material comprising a rubbery binder selected from the groupconsisting of natural rubber and synthetic, conjugated diene polymer andsufficient oxidant in admixture therewith to supply the oxygen necessaryfor combustion with substantial decomposition of said packing material,thereby rendering said material both ignitible and self-sustaining incombustion even in the absence of any external source of oxygen, andigniting said packing material in situ so that said packing materialsubstantially decomposes.

6. A method of packing oi and subsequently removing the packing materialfrom an oil well which comprises positioning in said well packingmaterial comprising a mixture of rubbery binder selected from the `groupconsistinlg of natural rubber and synthetic, conjugated diene polymerand from to 85 parts by weight per 100 parts of mixture of oxidantselected from the group consisting of ammonium nitrate, ammoniumperchlorate, potassium perchlorate, potassium nitrate, and mixturesthereof, thereby rendering said packing material both ignitible andself-sustaining in combustion to the substantial decomposition thereofeven in the absence of any external source of oxygen, and igniting saidpacking material in situ so that said packing material substantiallydecomposes.

7. A method according to claim 6 wherein said rubbery binder is a rubberhaving a Mooney (ML-4) value in the range of about 10 to 40.

8. The method of claim 4 wherein the body comprises from about 50 toabout 15 parts of a rubbery binder possessing a Mooney value not greaterthan and from about 50 to about 85 parts of an oxidant.

References Cited in the file of this patent UNITED STATES PATENTS1,249,180 Ostromislensky Dec. 4, 1917 2,138,156 Halliburton NOV. 29,1938 2,291,862 Bailey Aug. 4, 1942 2,624,603 Sweet Ian. 6, 1953

4. IN AN OPERATION WHEREIN THE APPLICATION OF A FORCE IS ADPATED TO BETEMPORARILY RESTRAINED AND SUBSEQUENTLY RELEASED, THE IMPROVED METHODWHICH COMPRISES POSITIONING IN THE PATH OF SAID FORCE A BODY CONSISTINGESSENTIALLY OF A COMPOSITION COMPRISING A RUBBERY BINDER SELECTED FROMTHE GROUP CONSISTING OF NATURAL RUBBER AND SYNTHETIC, CONJUGATED DIENEPOLYMER AND SUFFICIENT OXIDANT IN ADMIXTURE THEREWITH TO SUPPLY THEOXYGEN NECESSARY FOR CUMBUSTION WITH SUBSTANTIAL DECOMPOSITION OF SAIDBODY, THEREBY RENDERING SAID COMPOSITION BOTH IGNITIBLE ANDSELF-SUSTAINING IN COMBUSTION EVEN IN THE ABSENCE OF ANY EXTERNAL SOURCEOF OXYGEN, AND IGNITING SAID BODY IN SITU SO THAT SAID BODYSUBSTANTIALLY DECOMPOSES.